1 files changed, 92 insertions, 0 deletions
diff --git a/src/common/impl/netif_windows.c b/src/common/impl/netif_windows.c
new file mode 100644
index 0000000..7531ae0
--- /dev/null
+++ b/src/common/impl/netif_windows.c
@@ -0,0 +1,92 @@
+#include "common/netif.h"
+
+#include <ws2tcpip.h> // AF_INET6, IN6_IS_ADDR_UNSPECIFIED
+#include <iphlpapi.h>
+
+bool ffNetifGetDefaultRouteImplV4(FFNetifDefaultRouteResult* result) {
+    PMIB_IPFORWARD_TABLE2 pIpForwardTable = NULL;
+
+    if (!NETIO_SUCCESS(GetIpForwardTable2(AF_INET, &pIpForwardTable))) {
+        return false;
+    }
+
+    bool foundDefault = false;
+    uint32_t smallestMetric = UINT32_MAX;
+
+    for (ULONG i = 0; i < pIpForwardTable->NumEntries; ++i) {
+        MIB_IPFORWARD_ROW2* row = &pIpForwardTable->Table[i];
+
+        if (row->DestinationPrefix.PrefixLength == 0 &&
+            row->DestinationPrefix.Prefix.Ipv4.sin_addr.S_un.S_addr == 0) {
+            MIB_IF_ROW2 ifRow = {
+                .InterfaceIndex = row->InterfaceIndex,
+            };
+            if (NETIO_SUCCESS(GetIfEntry2(&ifRow)) && ifRow.OperStatus == IfOperStatusUp) {
+                MIB_IPINTERFACE_ROW ipInterfaceRow = {
+                    .Family = AF_INET,
+                    .InterfaceIndex = row->InterfaceIndex,
+                };
+
+                uint32_t realMetric = row->Metric /* Metric offset */;
+
+                if (NETIO_SUCCESS(GetIpInterfaceEntry(&ipInterfaceRow))) {
+                    realMetric += ipInterfaceRow.Metric /* Interface metric */;
+                }
+
+                if (realMetric < smallestMetric) {
+                    smallestMetric = realMetric;
+                    result->ifIndex = row->InterfaceIndex;
+                    foundDefault = true;
+                }
+            }
+        }
+    }
+
+    FreeMibTable(pIpForwardTable);
+
+    return foundDefault;
+}
+
+bool ffNetifGetDefaultRouteImplV6(FFNetifDefaultRouteResult* result) {
+    PMIB_IPFORWARD_TABLE2 pIpForwardTable = NULL;
+
+    if (!NETIO_SUCCESS(GetIpForwardTable2(AF_INET6, &pIpForwardTable))) {
+        return false;
+    }
+
+    bool foundDefault = false;
+    uint32_t smallestMetric = UINT32_MAX;
+
+    for (ULONG i = 0; i < pIpForwardTable->NumEntries; ++i) {
+        MIB_IPFORWARD_ROW2* row = &pIpForwardTable->Table[i];
+
+        if (row->DestinationPrefix.PrefixLength == 0 &&
+            IN6_IS_ADDR_UNSPECIFIED(&row->DestinationPrefix.Prefix.Ipv6.sin6_addr)) {
+            MIB_IF_ROW2 ifRow = {
+                .InterfaceIndex = row->InterfaceIndex,
+            };
+            if (NETIO_SUCCESS(GetIfEntry2(&ifRow)) && ifRow.OperStatus == IfOperStatusUp) {
+                MIB_IPINTERFACE_ROW ipInterfaceRow = {
+                    .Family = AF_INET6,
+                    .InterfaceIndex = row->InterfaceIndex,
+                };
+
+                uint32_t realMetric = row->Metric /* Metric offset */;
+
+                if (NETIO_SUCCESS(GetIpInterfaceEntry(&ipInterfaceRow))) {
+                    realMetric += ipInterfaceRow.Metric /* Interface metric */;
+                }
+
+                if (realMetric < smallestMetric) {
+                    smallestMetric = realMetric;
+                    result->ifIndex = row->InterfaceIndex;
+                    foundDefault = true;
+                }
+            }
+        }
+    }
+
+    FreeMibTable(pIpForwardTable);
+
+    return foundDefault;
+}